狂神說Java【SMBMS】——SMBMS超市訂單管理系統(三) ——登陸功能優化

1、注銷功能

​ 思路：移除session對象+返回登陸頁面

1.編寫servlet

package com.thhh.servlet.user;

import com.thhh.utils.Constants;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LogoutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.getSession().removeAttribute(Constants.USER_SESSION);//移除用戶session
        resp.sendRedirect(req.getContextPath()+"/login.jsp");//重定向回登陸頁面
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

2.注冊servlet

<!--注冊注銷servlet-->
<servlet>
    <servlet-name>LogoutServlet</servlet-name>
    <servlet-class>com.thhh.servlet.user.LogoutServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>LogoutServlet</servlet-name>
    <url-pattern>/jsp/logout.do</url-pattern>
</servlet-mapping>

2、登陸攔截優化

1.編寫過濾器

package com.thhh.filter;

import com.thhh.pojo.User;
import com.thhh.utils.Constants;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class SysFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)req;//父類強轉子類,用於獲取session
        HttpServletResponse response = (HttpServletResponse) resp;//父類強轉子類，用於重定向
        User user = (User) request.getSession().getAttribute(Constants.USER_SESSION);

        if (user==null){//用戶處於未登陸狀態
            response.sendRedirect(request.getContextPath()+"/error.jsp");//重定向到登陸頁面
        }else{
            chain.doFilter(req,resp);//過濾器放行
        }
    }

    @Override
    public void destroy() {

    }
}

2.注冊過濾器

<!--注冊未登錄時請求后台頁面過濾器-->
<filter>
    <filter-name>SysFilter</filter-name>
    <filter-class>com.thhh.filter.SysFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>SysFilter</filter-name>
    <url-pattern>/jsp/*</url-pattern>
    <!--注意：我們將所有需要登陸之后才能訪問的功能性頁面給都放在了/jsp文件夾下，所以過濾器應該過濾這個文件夾下的請求-->
</filter-mapping>

3.導入error頁面

4.測試功能



測試完成！